Field of the Invention
The present invention relates to a coating mist collection apparatus that collects coating mist contained in processing target air discharged from a coating chamber, and, specifically,
relates to a coating mist collection apparatus that includes: a filter that collects coating mist contained in processing target air discharged from a coating chamber; and a powder nozzle that is arranged in an air guiding passage for guiding processing target air to the filter, and sprays a powder into the processing target air passing through the air guiding passage, wherein due to the processing target air that contains the dispersed powder sprayed from the powder nozzle being passed through the filter, the coating mist in the processing target gas is collected by the filter in a state in which a coating mist trapping filter covering layer made up of an accumulated powder layer is formed on the surface of the filter.
Description of Related Art
Patent Document 1 discloses a coating mist collection apparatus in which, in an air guiding passage (7, 8) through which processing target air that contains coating mist and was discharged from a coating chamber (1) is guided to a bag filter (11), a powder (assisting dust) is sprayed from a powder nozzle (26) into the processing target air passing through the air guiding passage (7, 8), and thus the coating mist in the processing target air is collected by the bag filter (11) in a state in which a coating mist trapping filter covering layer made up of an accumulated powder layer is formed on the surface of the bag filter (11) (note that the numbers in parentheses are the reference numerals used in Patent Document 1).
With the conventional coating mist collection apparatus disclosed in Patent Document 1, powder containing the coating mist that falls from the surface of the bag filter (11) during regeneration of the bag filter (11) by so-called reverse air cleaning or the like (i.e., the powder with the mixed coating material that had previously formed the coating mist trapping filter covering layer) is received by a receiving hopper (13) and then sent to a stock hopper (20) by a conveying means (13.1) that includes a conveying rate adjustment function, and then a portion of the powder containing the coating mist received by the stock hopper (20) is retrieved from the stock hopper (20) through a powder discharge passage (27) and sent to a re-processing system.
The powder containing the coating mist remaining in the stock hopper (20) is replenished with a measured amount of fresh powder not containing the coating mist so as to reduce the average coating mist content percentage of the powder overall in the stock hopper (20), and the powder whose coating mist content percentage was reduced in this way is retrieved from the stock hopper (20) through a powder retrieval passage (23) and supplied by force feeding to the powder nozzle (26) through a powder supply passage (25) along with carrier air by a pneumatic conveyor (24).
In other words, with this coating mist collection apparatus, a portion of the powder containing the coating mist that falls from the bag filter (11) is mixed with fresh powder so as to reduce the average coating mist content percentage, and then re-sprayed from the powder nozzle (26) for cyclic usage.
Also, with the coating mist collection apparatus disclosed in Patent Document 1, it has been proposed to keep the powder containing the coating mist in the receiving hopper (13) (i.e., the powder having an increased bridging tendency due to containing the coating mist) in a dissolved state or fluidized state using a pneumatic system, and to keep the powder containing the coating mist in the stock hopper (20) in a dissolved and fluidized state using a fluidizing apparatus.